jkleban
Well... just for your complete research, I will say that BFD3's new kits are absolutely the most realistic drum kits released to date (I have a ton of them).  The vintage GRETSCH kit (purple) that comes with BFD3 is a super "live" sounding kit with all kinds of articulations and room mics.  Very realistic MIDI drum tracks possible.
 
Like I mentioned earlier, the AD PAK of the modern JAZZ kit (sticks) are also very, very good.

FYI - John Emmerich was half of the team that worked on the BFD samples. His work is always excellent; however I particularly like what he did with Zildjian's Gen16 Digital Vault of cymbal samples. My father was a jazz drummer, so I grew up knowing what cymbals sound like and John's are the best I've heard. To my ears, his sampled cymbals capture the openness and air of real cymbals.

+1 on the GENPAK collection (I have all three).  Because of them, most of my projects include BFD and another kit piece product (AD, SD or Abbey Road - vintage).  The GENPAK cymbals and their air are easily commingled like this.  Did you ever see John play that crazy looking drum controller that somewhat looks like bagpipes  ?
 
So, if one already had AD1 full (with most ADPAKs) and every plugin needed to mix drums, is it worth the upgrade to AD2 (down to the wire on price timing for the update)?
 
Jim

jkleban
 is it worth the upgrade to AD2 (down to the wire on price timing for the update)?
 

It is not like it won't go on sale or maybe be bundled with a future version of SONAR.

jkleban
PS - but what is the difference between AD1 and AD2?

Jim -
 
This video does a good job of demoing the differences. Stick it out to the end - the FX and editing improvements are what sold me, not the "gallery" that they show in the beginning.